Sump systems are commonly used to collect and remove excess water from a given area. One of the most common uses of a sump system is to remove excess water from around the foundation and or basement regions of a building in order to prevent water from seeping into the basement regions and/or negatively impacting the loadbearing capacities of the footings. A common design includes a water drainage system extending along the footings of the building, such as a buried tile and/or water collection and flow channel that drains via a drain line into a sump pit recessed into the ground within the basement, preferably below the level of the footings. A sump pump is arranged to pump out the water collected within the sump pit, either continuously or, more commonly, when the level of the water within the sump pit reaches some maximum level. When the groundwater level around the foundation of the building rises above the level of the drainage system, the groundwater seeps into the drainage system, which directs the water to the drain line and into the sump pit, where the water is eventually ejected by the pump to a location remote from the building, such as a sewer system or drainage field. In this way, the sump system lowers the local groundwater level in the immediate area of the building foundation and/or the basement floor, which can prevent ingress of water into the basement and/or other problems associated with the elevated local groundwater level around the foundation and/or basement.
The expected parameters for functioning of such a sump system depends closely upon the normal conditions of the local groundwater level. For example, in many circumstances, the local groundwater level may normally be located below the level of the building foundations, and the local groundwater level may only temporarily rise above the level of the foundations or the ground surrounding the foundations may become temporarily saturated during rain events. This circumstance may cause temporary problems with ingress of water into the basement of the building. In this circumstance, a sump system need only function during such times that the local groundwater level or soil saturation surrounding the foundation and/or basement rises above the level of the basement. In other circumstances, the foundation and/or basement of the building may be disposed at or below the usual local groundwater level. In these circumstances, it is assumed that the sump pump will need to run substantially continuously, although it is still possible that the sump pump could run only intermittently, that is, it alternates between periods of pumping and periods of not pumping. The remaining discussion assumes a sump system that operates such that the sump pump runs intermittently.
Many sump systems encounter a problem when water enters the sump pump pit faster than it can be ejected by the sump pump. For example, during and immediately after an intense rainfall event, ground water drains into the drainage system and subsequently flows into the sump pit at an increased flow rate. Sometimes, when an extremely intense rainfall event occurs, the flow rate of water into the sump pit from the drainage system exceeds the capacity of the sump pump discharge rate. When this event occurs, the sump pump is overwhelmed with inflowing ground water. The sump pit then fills completely with excess water and overflows the rim of the sump pit even though the sump pump is fully functional. Such overflowing water may then spread across the basement floor, causing damage to items in the basement. Although rainfall events of such intensity are relatively rare, when they do occur, the maximum pumping capacity of the sump pump can be temporarily overwhelmed, and damage to property in the basement can result.
Various attempts to prevent the sump pump from being overwhelmed during an intense rainfall event have been made in the past. In one design, an alarm system provides a warning signal when the water in the sump pit rises above a predefined level. However, this design does not prevent an overflow from happening. In other designs, a secondary sump pump is installed in the sump pit and arranged to run only when the primary sump pump is overwhelmed. One such design includes also dividing the sump pit into a primary reservoir for the primary pump and a secondary reservoir for the secondary pump. However, these design require the complication and expense of adding a second pump and associated control systems, as well as often requiring additional structures to the sump pit. Yet further designs provide a water-tight cover sealed over the sump pit to prevent excess water from flowing out of the sump pit. However, these designs require extensive modifications to the sump pit and can create an excessive water pressure within the sump pit, which could lead to catastrophic failure of the cover. Therefore, it would be desirable to have a sump system that prevents overflow of the sump pit without requiring significant complicated alterations to the sump pit or additional pumps and control systems.